Patients with cardiopulmonary failure can be treated with mechanical circulatory support, such as veno-arterial extra-corporeal membrane oxygenation (VA ECMO). In association with VA ECMO, a cannula having a proximal end and a distal tip is placed in an artery, which is commonly the femoral artery, to infuse oxygenated blood into the body. The cannula can be inserted into the artery by way of open surgical or percutaneous puncture, such as through the Seldinger technique. Blood that is directed into the cannula's proximal end exits the cannula at its distal tip, and is directed up the aorta towards the heart.
In order to supply an adequate amount of blood, the cannula needs to be sufficiently large in diameter. As a result, the cannula itself obstructs blood flow into the extremity or limb that is cannulated, which is commonly a leg. For patients on long-term support, the potential for ischemia to the cannulated limb arises due to this obstruction of blood flow. Attempts to solve this ischemia problem include the insertion of a second arterial cannula into the artery, limb-wise distal to the site of cannulation and directed downwards. This second cannula is taken off of the cardiopulmonary circuit by a Y connector and a tube. Unfortunately, this requires a second cannulation in an often sick and anticoagulated patient.
A need exists for an arterial cannula that provides adequate blood flow into the body, but which also enables blood flow into the cannulated body extremity.